Six boys have been arrested after someone reported being chased by a group of people armed with a gun behind a Milton high school.

Bishop Reding Catholic Secondary School, on Main Street East, was placed on lockdown sometime after 12 p.m. after receiving what the school described as a “reported threat.”

About an hour later, Halton Regional Police confirmed that four youths had been detained in connection with the incident. Thirty minutes after that, police said a total of seven young people had been taken into custody.

Police later revealed that the lockdown at the school stemmed from a call they received from a victim who said they were being chased by a group of males with a gun behind the school.

“I don’t know the number of people who were being chased or the number of people chasing. I think it was a group that was being chased by a (another) group,” Const. Ryan Anderson said.

“That chase led them through Lions Sports Park and towards Milton Memorial Arena. The police investigation then led us back to the high school.”

One student told CTV News Toronto that he saw four or five police officers and three of them had what appeared to be assault rifles.

“It was calm,” Nicolas said. “They didn’t go and rip ‘em up. They just asked them to get up and they did. They cooperated.”

“I saw a guy getting arrested at the front entrance,” another student said. “We saw a whole bunch of police cars, police officers walking all around the school. It was a lot going on.”

Parents of students at that school were asked to stay clear of the area while police secured the scene.

Anderson said officers quickly located seven young males at the school and detained them. One of the boys has since been released. The other six remain in police custody.

In a news release issued Thursday evening, police said that officers recovered a knife and a pellet gun during the course of the investigation.

“An airsoft gun that was initially thought to be part of this incident is confirmed to be unrelated,” police said in the release.

There was no word on charges. Police also could not say if those in custody are students at Bishop Reding.

“Anytime we’re finding weapons inside a school we’re very concerned. It’s not something we want to see and we take it very seriously,” Anderson said.

“We’ve been in contact with the school. I don’t know what their procedures will be in the coming days.”

The lockdown order was later lifted and students were released early so officers could comb the building for evidence.

Nearby schools Chris Hadfield Public school and St. Peter Catholic Elementary School were briefly placed on hold and secure, but those orders have since been lifted. Police said regular operations have resumed at those schools